1. Technical Field
The present invention relates in general to an improved method and apparatus for processing sliders and, in particular, to an improved method and apparatus for directly debonding sliders during single slider processing.
2. Description of the Related Art
Generally, a data access and storage system consists of one or more storage devices that store data on magnetic or optical storage media. For example, a magnetic storage device is known as a direct access storage device (DASD) or a hard disk drive (HDD) and includes one or more disks and a disk controller to manage local operations concerning the disks. The hard disks themselves are usually made of aluminum alloy or a mixture of glass and ceramic, and are covered with a magnetic coating. Typically, one to six disks are stacked vertically on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm).
A typical HDD also utilizes an actuator assembly. The actuator moves magnetic read/write heads to the desired location on the rotating disk so as to write information to or read data from that location. Within most HDDs, the magnetic read/write head is mounted on a slider. A slider generally serves to mechanically support the head and any electrical connections between the head and the rest of the disk drive system. The slider is aerodynamically shaped to glide over moving air in order to maintain a uniform distance from the surface of the rotating disk, thereby preventing the head from undesirably contacting the disk.
Typically, a slider is formed with an aerodynamic pattern of protrusions on its air bearing surface (ABS) that enables the slider to fly at a constant height close to the disk during operation of the disk drive. A slider is associated with each side of each platter and flies just over the platter's surface. Each slider is mounted on a suspension to form a head gimbal assembly (HGA). The HGA is then attached to a semi-rigid actuator arm that supports the entire head flying unit. Several semi-rigid arms may be combined to form a single movable unit having either a linear bearing or a rotary pivotal bearing system.
The head and arm assembly is linearly or pivotally moved utilizing a magnet/coil structure that is often called a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which the spindle is also mounted. The base casting with its spindle, actuator VCM, and internal filtration system is then enclosed with a cover and seal assembly to ensure that no contaminants can enter and adversely affect the reliability of the slider flying over the disk. When current is fed to the motor, the VCM develops force or torque that is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head approaches a desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop and settle directly over the desired track.
Historically, the sliders (and their magnetic heads) used in computer hard drives have been processed by depositing thin films onto ceramic wafers which are then cut into strips which are called “rows.” These rows are then lapped to specified dimensional tolerances after which a pattern, e.g., an “air bearing surface” or ABS, is etched into the top surface of the rows that will allow the slider to fly above the disk at a specific fly height. At the end of manufacturing, these rows are cut into individual sliders which are attached to suspensions and built into the hard disk drives.
Flying the sliders of hard disk drives closer to the magnetic disks increases aerial density, which increases the capacity of the hard disk drives. In order to fly closer to the disks, the dimensional tolerances to which sliders are lapped are getting tighter as the technology evolves. It is this tightening of lapping tolerances that has forced the industry into lapping the individual sliders instead of lapping entire rows of unseparated sliders. This lapping of individual sliders is also known as “single slider processing.”
One significant challenge in single slider processing is the bonding of the individual sliders onto a process carrier (for ABS etching), and the subsequent steps of debonding, cleaning, and inspection, which were historically done at the row level. Since the equipment used for the ABS etching is expensive, the goal has been to bond the individual sliders in a tightly spaced array to maximize the batch processes involved with the etching. This means that hundreds of these sliders are bonded to a carrier, etched, and then debonded, cleaned and shipped.
Since the etching process is a photolithography process which involves spin-on resists, the surfaces of the carriers of the sliders must be extremely planer in order to evenly distribute the resist substances. For this reason, the gaps between the individual sliders are filled with a planerization material which makes the entire surface of the carrier planer. However, one of the more serious problems encountered was how to debond the sliders from their carrier without damaging the sliders, and then present them for cleaning, inspection, and shipping. Thus, an improved method and/or apparatus for directly debonding the individual sliders during single slider processing which reduces the incidence of slider damage would be very desirable.